In lightweight construction, in particular in aircraft construction and in aerospace, fibre reinforced composite components, which have a high weight saving potential on account of their extremely high strength with at the same time low mass, are increasingly being used for load-bearing structural components. With high requirements expected of the mechanical properties, the composite components are formed with carbon-fibre reinforced epoxy resins. This involves arranging one on top of the other, or stacking, a multiplicity of layers with carbon fibres that are impregnated with epoxy resin. Here, the layers each have different fibre orientations, in order to optimize the finished composite component for specific directions of loading. The fibre orientations in the respective layers may be, for example, 0° and ±45°. For producing such composite components, it is particularly preferred to use a so-called CRP prepreg material, which is formed with carbon fibres already preimpregnated (saturated) with a suitable epoxy resin to form a resin matrix. Here, the carbon fibres may be arranged in the form of a woven fabric, a scrim or rovings, that is to say in the form of oriented fibre strands. The curing of the CRP prepreg material takes place in a known way, for example in vacuum bags in autoclaves or the like.
To allow the composite components to be connected to other structural components, boreholes must be introduced into the composite components, so that for example bolts can be introduced for connection to further components. However, the embedding strength of composite components is not very high in comparison with the tensile or compressive strength on account of the carbon fibres generally running parallel to the surfaces of the component. It is therefore necessary to provide additional mechanical reinforcements in areas of force introduction and/or connecting areas, for example in the form of boreholes to produce a bolted or riveted connection.
These mechanical reinforcements may be formed for example as so-called doublers. Doublers comprise additional layers of the composite material applied to the actual composite component in areas of force introduction and/or connecting areas. However, the doublers have the disadvantage that they allow thickenings to be created in the areas of force introduction or connecting areas, often leading to restrictions in the structural design.
Furthermore, it is known to integrate planar metallic sheet-like formations in the layer structure, in particular in areas of force introduction or connecting areas, of a composite component. This involves alternately stacking layers of the metallic sheet-like formations and the CRP prepreg material one on top of the other. The combination of the high embedding strength of the metallic sheet-like formations together with the high tensile or compressive strength of the composite material conjointly produce advantageous mechanical properties even in areas of force introduction or connecting areas.
However, the integration of layers of a sheet-like formation in the layer structure of the CRP composite component to improve the mechanical properties in areas of force introduction or connecting areas, for example in the form of boreholes to produce bolted or riveted connections between composite components or the like, has previously been too complex in production engineering terms and, if carried out at all, has so far only been partly automated.